Environmentally friendly and degradable bioadhesive and preparation method thereof

Abstract

The present invention discloses an environmentally friendly and degradable bioadhesive and a preparation method thereof, belonging to the technical field of macromolecular adhesive preparation. The preparation method comprises the following steps: a pre-activated gallic acid mixture, a pre-activated oxidized hyaluronic acid mixture, and a diamine cross-linking agent are reacted at 20°C to 25°C for 15 to 20 hours, followed by dialysis treatment to obtain a gallic acid-oxidized hyaluronic acid mixture; the gallic acid-oxidized hyaluronic acid mixture is mixed, stirred, and allowed to stand with an aminopolysaccharide dispersion to obtain the bioadhesive. The present invention first reacts gallic acid and oxidized hyaluronic acid with a diamine cross-linking agent to obtain a gallic acid-oxidized hyaluronic acid mixture, which is then mixed and cross-linked with an aminopolysaccharide dispersion to form a bioadhesive having good adhesive properties, antibacterial properties, and breathability.

Description

Technical Field

[0001] The present invention belongs to the technical field of macromolecular adhesive preparation, and in particular relates to an environmentally friendly and degradable bioadhesive and a preparation method thereof. Background Art

[0002] As a type of soft and wet material with a three-dimensional network structure, hydrogels have unique physical and chemical properties that make them show irreplaceable application value in the biomedical field. The porous structure and high water content that are highly similar to the natural extracellular matrix (ECM) not only give them excellent biocompatibility, but also support key biological processes such as cell adhesion and nutrient transport. Hydrogels are mainly composed of hydrophilic polymer materials. Hydrogels composed of hydrophilic polymer materials usually have a porous structure and a high water content, allowing gas and liquid to permeate. With the continuous deepening of research on hydrogels, various functional hydrogels have been reported one after another, such as stimulus-responsive hydrogels, self-healing hydrogels, adhesive hydrogels, antibacterial hydrogels, etc. These hydrogels combine with their surfaces through physical or chemical interactions at the interface with the matrix material, that is, the hydrogels can adhere to the surface of the matrix material (such as metal, glass, plastic, pig skin tissue, etc.) to achieve specific functions. In recent years, through the cross-integration of materials chemistry, bioengineering and clinical medicine, the research on hydrogels in bioadhesive materials has moved from basic functional development to the stage of precision and intelligent innovation. Bioadhesives are adhesive materials prepared by biotechnology or modification of natural materials, used to replace or supplement traditional chemical adhesives, with biocompatibility, degradability and functional advantages. According to the source of raw materials and preparation methods, they can be divided into the following two categories: (1) Natural bioadhesives. Based on natural polymer materials, such as collagen, chitosan, fibrin, tannin, lignin, etc. For example, collagen adhesives are widely used in skin and soft tissue repair because of their similarity to human tissue components. (2) Synthetic bioadhesives. Materials prepared by chemical synthesis or bioengineering, such as polylactic acid (PLA), polyethylene glycol (PEG), polyurethane (PU), etc. However, most hydrogel adhesives currently have some problems: (1) the preparation method is complex, requiring the design of complex molecular structures; (2) the adhesion strength is not high enough, and can only show adhesion to specific materials; (3) the mechanical properties are poor; (4) the poor air permeability during use makes it easy to get infected, which is not conducive to wound recovery; (5) the lack of antibacterial activity required for the application of materials to easily infected wounds. To this end, some new and improved technologies have been adopted in the existing technology to solve these technical problems.

[0003] Patent CN116549712A discloses a degradable healing-promoting medical adhesive and a preparation method thereof. The invention mixes oxidized sodium alginate and modified alginate microspheres loaded with growth factors in proportion to obtain component A; then carboxymethyl chitosan and modified polylysine are added to water and dissolved to obtain a mixed solution of carboxymethyl chitosan and modified polylysine; then a thickener is dissolved in the mixed solution of carboxymethyl chitosan and modified polylysine to obtain component B; when used, the two are mixed and extruded to achieve a bonding effect.

[0004] Patent CN116173286A discloses a medical adhesive, its preparation method, and application. The invention dissolves modified sodium alginate, tannic acid, and an inorganic substance capable of producing divalent metal cations in water to obtain liquid A; dissolves a positively charged polymer, a nano-composite antibacterial agent, and gluconolactone in water to obtain liquid B; and after evenly mixing liquids A and B, a medical adhesive is obtained, achieving good adhesion, mechanical properties, and antibacterial properties.

[0005] The above-mentioned improvements mainly utilize natural polymer materials such as sodium alginate and carboxymethyl chitosan, and achieve an improvement in the bonding effect by mixing them with other additives. Although natural polymer materials such as sodium alginate and carboxymethyl chitosan are non-toxic to the human body, have good in vitro degradation properties and are environmentally friendly, their adhesion is often low when used in low concentrations, and the concentration needs to be increased to have good adhesion properties. Although increasing the concentration has a good effect on improving adhesion properties, too high a concentration not only causes the adhesive to solidify, but sometimes the liquid often causes excessive cross-linking, resulting in poor air permeability. Poor air permeability makes the wound susceptible to bacterial infection, which has a significant negative impact on wound recovery.

[0006] Therefore, it is of great significance to use natural polymer materials to prepare adhesives with good bonding properties while improving air permeability. Summary of the Invention

[0007] To address the shortcomings of the prior art, the present invention first reacts gallic acid and oxidized hyaluronic acid with a diamine crosslinker to produce a gallic acid-oxidized hyaluronic acid mixture, which is then mixed and cross-linked with an aminopolysaccharide dispersion to form a bioadhesive, thereby solving the technical problems raised in the background art. Specifically, the technical solution of the present invention includes the following:

[0008] A second object of the present invention is to provide a method for preparing an environmentally friendly and degradable bioadhesive, the method comprising the following steps:

[0009] The preactivated gallic acid mixture, the preactivated oxidized hyaluronic acid mixture and the diamine cross-linking agent are reacted at 20° C. to 25° C. for 15 to 20 hours, and then dialyzed to obtain a gallic acid-oxidized hyaluronic acid mixture;

[0010] The gallic acid-oxidized hyaluronic acid mixed solution and the aminopolysaccharide dispersion solution are mixed, stirred, and allowed to stand to obtain the bioadhesive.

[0011] Furthermore, the preparation method of the pre-activated gallic acid mixture comprises the following steps:

[0012] Gallic acid, dimethyl sulfoxide, 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride and 1-hydroxybenzotriazole are mixed and dispersed, stirred and activated at 10° C. to 15° C. for 15 to 20 minutes to obtain the pre-activated gallic acid mixture.

[0013] Furthermore, the weight ratio of gallic acid: dimethyl sulfoxide: 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride: 1-hydroxybenzotriazole is 1:200-300:1-1.5:1-1.5.

[0014] Furthermore, the preparation method of the pre-activated oxidized hyaluronic acid mixture comprises the following steps:

[0015] Hyaluronic acid, deionized water, and sodium periodate are mixed and dispersed in a light-proof environment, and then reacted at 25°C to 30°C for 10 hours to 12 hours, followed by dialyzation and freezing to obtain oxidized hyaluronic acid;

[0016] The oxidized hyaluronic acid, dimethyl sulfoxide, 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride and 1-hydroxybenzotriazole are mixed and dispersed and stirred at 10° C. to 15° C. for activation for 15 to 20 minutes to obtain the pre-activated oxidized hyaluronic acid mixed solution.

[0017] Furthermore, the weight ratio of hyaluronic acid: deionized water: sodium periodate is 1:100-150:0.5-1.

[0018] Furthermore, the weight ratio of the oxidized hyaluronic acid: dimethyl sulfoxide: 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride: 1-hydroxybenzotriazole is 1:150-200:1-1.5:1-1.5.

[0019] Furthermore, the diamine cross-linking agent includes 1,4-butanediamine or 1,6-hexanediamine.

[0020] Furthermore, the weight ratio of the pre-activated gallic acid mixture: the pre-activated oxidized hyaluronic acid mixture: the diamine cross-linking agent is 1:5-7:0.01-0.02.

[0021] Furthermore, the aminopolysaccharide dispersion is prepared by mixing and dispersing chitosan and anhydrous ethanol in a weight ratio of 1:100 to 120.

[0022] Furthermore, the weight ratio of the gallic acid-oxidized hyaluronic acid mixture to the aminopolysaccharide dispersion is 1:1-3.

[0023] A second object of the present invention is to provide a bioadhesive prepared by a method for preparing an environmentally friendly and degradable bioadhesive.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] The present invention utilizes the principles of molecular biomimetic to mimic the adhesive properties of mussel mucin, which has good adhesion properties due to the oxidative self-polymerization crosslinking between the polyphenolic hydroxyl groups and amino groups on the DOPA structure. Gallic acid with a polyphenolic hydroxyl structure is used as one of the raw materials. First, hyaluronic acid, a natural polymer material with a carboxyl structure, is oxidized to a certain extent, so that the adjacent dihydroxy groups on its structure are broken to generate aldehyde groups, thereby obtaining oxidized hyaluronic acid. The carboxyl groups on the gallic acid and oxidized hyaluronic acid are then pre-activated, and then mixed and stirred with a diamine crosslinker to react with amidation condensation to obtain a gallic acid-oxidized hyaluronic acid mixture. The gallic acid-oxidized hyaluronic acid mixture is then mixed and cross-linked with an amino polysaccharide dispersion to form a bioadhesive. The diamine crosslinker not only allows gallic acid to chemically condense onto the oxidized hyaluronic acid, but also has a longer carbon chain that can increase the flexibility of the molecular chain, reduce the resistance to segment motion, expand the molecular pores, and increase the gaps between segments, thereby improving air permeability. Excessive oxidation of hyaluronic acid can lead to an excess of aldehyde functional groups. When the gallic acid-oxidized hyaluronic acid mixture is cross-linked with an amino polysaccharide dispersion, this leads to excessive aldehyde groups binding to the amino groups on the amino polysaccharide. This, in turn, results in poor oxidative polymerization crosslinking between the phenolic hydroxyl groups and the amino groups in the resulting bioadhesive, resulting in poor adhesion. The synergistic combination of gallic acid and chitosan not only ensures good adhesion through the formation of oxidative autopolymerization crosslinks between the polyphenolic hydroxyl groups and the amino groups, but also enhances the antibacterial properties of the bioadhesive. DETAILED DESCRIPTION

[0026] The following will clearly and completely describe the technical solutions of the present invention through the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without making any creative efforts shall fall within the scope of protection of the present invention.

[0027] Unless otherwise specified, the raw materials and reagents used in the present invention are commercially available or can be prepared by known methods.

[0028] Preparation Example 1:

[0029] The preparation method of the pre-activated gallic acid mixed solution specifically includes the following steps:

[0030] 400 g of dimethyl sulfoxide was weighed and placed in a flask, which was then placed in a temperature environment of 10° C. 2 g of gallic acid, 2 g of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride, and 2 g of 1-hydroxybenzotriazole were weighed and added to the dimethyl sulfoxide. The mixture was stirred at a temperature of 10° C. and activated at a stirring speed of 100 r / min for 15 minutes to obtain a pre-activated gallic acid mixture.

[0031] Preparation Example 2:

[0032] The preparation method of the pre-activated gallic acid mixed solution specifically includes the following steps:

[0033] 500 g of dimethyl sulfoxide was weighed and placed in a flask, which was then placed in a temperature environment of 10° C. At this time, 2 g of gallic acid, 3 g of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride, and 2.5 g of 1-hydroxybenzotriazole were weighed and added to the dimethyl sulfoxide. The mixture was stirred at a temperature of 10° C. and activated at a stirring speed of 100 r / min for 20 minutes to obtain a pre-activated gallic acid mixture.

[0034] Preparation Example: 3:

[0035] The preparation method of the pre-activated gallic acid mixed solution specifically includes the following steps:

[0036] 600 g of dimethyl sulfoxide was weighed and placed in a flask, which was then placed in a temperature environment of 15° C. 2 g of gallic acid, 3 g of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride, and 3 g of 1-hydroxybenzotriazole were weighed and added to the dimethyl sulfoxide. The mixture was stirred at a temperature of 15° C. and activated at a stirring speed of 100 r / min for 20 minutes to obtain a pre-activated gallic acid mixture.

[0037] Preparation Example 4:

[0038] The preparation method of the pre-activated oxidized hyaluronic acid mixture specifically includes the following steps:

[0039] Weigh 5g of hyaluronic acid powder and add it to 500g of deionized water and stir continuously at a speed of 400r / min until a uniform and transparent solution is formed (during this period, appropriate heating can be used to promote the dissolution and dispersion of hyaluronic acid, but it must be cooled to room temperature before adding sodium periodate). Then add 2.5g of sodium periodate, mix and stir, and immediately place it in a dark environment, and then control the reaction temperature to 25°C, and react in the dark for 10 hours in this temperature environment. Once the reaction time is up, immediately add 10g of ethylene glycol and continue stirring the reaction for 2 hours to fully quench the sodium periodate. The final reaction solution is mixed with an equal volume of anhydrous ethanol and stirred until turbid, then placed in a dialysis bag with a cutoff flow of 3.5kDa, dialyzed with deionized water for 2 days, and finally freeze-dried the dialyzed product solution using a freeze dryer to obtain oxidized hyaluronic acid. The aldehyde concentration of oxidized hyaluronic acid was measured to be 2.17mmol / g by the "hydroxylamine hydrochloride-potentiometric titration method";

[0040] 300 g of dimethyl sulfoxide was weighed and placed in a flask, which was then placed in a 10°C environment. 2 g of oxidized hyaluronic acid was then weighed and added to the dimethyl sulfoxide and ultrasonically dispersed at 300 W for 10 minutes. After the ultrasonic treatment, 2 g of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride and 2 g of 1-hydroxybenzotriazole were added, and the mixture was stirred at 100 rpm for 15 minutes, maintaining a temperature of 10°C and activating the mixture. A pre-activated oxidized hyaluronic acid mixture was obtained.

[0041] Preparation Example 5:

[0042] The preparation method of the pre-activated oxidized hyaluronic acid mixture specifically includes the following steps:

[0043] Weigh 5g of hyaluronic acid powder and add it to 700g of deionized water and stir continuously at a speed of 400r / min until a uniform and transparent solution is formed (appropriate heating can be used to promote the dissolution and dispersion of hyaluronic acid, but it must be cooled to room temperature before adding sodium periodate). Then add 4g of sodium periodate, mix and stir, and immediately place it in a dark environment, and then control the reaction temperature to 25°C. In this temperature environment, avoid light and react for 11 hours. Once the reaction time is up, immediately add 10g of ethylene glycol and continue stirring the reaction for 2 hours to fully quench the sodium periodate. The final reaction solution is mixed with an equal volume of anhydrous ethanol and stirred until turbid, then placed in a dialysis bag with a cutoff flow of 3.5kDa, dialyzed with deionized water for 2 days, and finally freeze-dried using a freeze dryer to obtain oxidized hyaluronic acid. The aldehyde concentration of oxidized hyaluronic acid was measured to be 2.32mmol / g by the "hydroxylamine hydrochloride-potentiometric titration method";

[0044] 350 g of dimethyl sulfoxide was weighed and placed in a flask, which was then placed in a 10°C environment. 2 g of oxidized hyaluronic acid was then weighed and added to the dimethyl sulfoxide and ultrasonically dispersed at 300 W for 10 minutes. After the ultrasonic treatment, 3 g of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride and 2 g of 1-hydroxybenzotriazole were added, and the mixture was stirred at 100 rpm for 20 minutes, maintaining the temperature at 10°C. The mixture was activated to obtain a pre-activated oxidized hyaluronic acid mixture.

[0045] Preparation Example 6:

[0046] The preparation method of the pre-activated oxidized hyaluronic acid mixture specifically includes the following steps:

[0047] Weigh 5g of hyaluronic acid powder and add it to 750g of deionized water and stir continuously at a speed of 400r / min until a uniform and transparent solution is formed (during this period, appropriate heating can be used to promote the dissolution and dispersion of hyaluronic acid, but it must be cooled to room temperature before adding sodium periodate). Then add 5g of sodium periodate, mix and stir, and immediately place it in a dark environment, and then control the reaction temperature to 30°C, and react in the dark for 12 hours at this temperature. Once the reaction time is up, immediately add 10g of ethylene glycol and continue stirring the reaction for 2 hours to fully quench the sodium periodate. The final reaction solution is mixed with an equal volume of anhydrous ethanol and stirred until turbid, then placed in a dialysis bag with a cutoff flow of 3.5kDa, dialyzed with deionized water for 2 days, and finally freeze-dried the dialyzed product solution using a freeze dryer to obtain oxidized hyaluronic acid. The aldehyde concentration of oxidized hyaluronic acid was measured to be 2.38mmol / g by the "hydroxylamine hydrochloride-potentiometric titration method";

[0048] 400 g of dimethyl sulfoxide was weighed and placed in a flask, which was then placed in a 15°C environment. 2 g of oxidized hyaluronic acid was then weighed and added to the dimethyl sulfoxide and ultrasonically dispersed at 300 W for 10 minutes. After the ultrasonic treatment, 3 g of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride and 3 g of 1-hydroxybenzotriazole were added, and the mixture was stirred at 15°C and activated at 100 rpm for 20 minutes to obtain a pre-activated oxidized hyaluronic acid mixture.

[0049] Preparation Example 7:

[0050] The preparation method of the pre-activated oxidized hyaluronic acid mixture specifically includes the following steps:

[0051] The amount of sodium periodate used in Preparation Example 6 was increased to 7 g, the light-proof reaction time was increased to 15 h, and the aldehyde group concentration of the oxidized hyaluronic acid was measured by the "hydroxylamine hydrochloride-potentiometric titration method" to be 3.05 mmol / g; the other conditions remained the same as in Preparation Example 6.

[0052] Example 1:

[0053] A method for preparing an environmentally friendly and degradable bioadhesive comprises the following steps:

[0054] Weigh 1 part by weight of the preactivated gallic acid mixture obtained in Preparation Example 1, 5 parts by weight of the preactivated oxidized hyaluronic acid mixture obtained in Preparation Example 4, and 0.01 part by weight of 1,4-butanediamine, and stir until uniformly dispersed. Then, stir at 200 rpm at 20°C for 15 hours. After the reaction, place the reaction solution in a 3.5 kDa dialysis bag and dialyze against deionized water for 2 days to obtain a gallic acid-oxidized hyaluronic acid mixture.

[0055] Weigh 1 part by weight of a gallic acid-oxidized hyaluronic acid mixture and 1 part by weight of a chitosan dispersion (chitosan and anhydrous ethanol are mixed in a weight ratio of 1:100 and placed in an ultrasonic disperser, and ultrasonically treated at a power of 400 W for 20 minutes to obtain a chitosan dispersion), mix and stir, then place in a 37°C water bath and let stand until a glue is formed to complete the preparation of the bioadhesive.

[0056] Example 2:

[0057] A method for preparing an environmentally friendly and degradable bioadhesive comprises the following steps:

[0058] Weigh 1 part by weight of the preactivated gallic acid mixture obtained in Preparation Example 2, 6 parts by weight of the preactivated oxidized hyaluronic acid mixture obtained in Preparation Example 5, and 0.015 parts by weight of 1,4-butanediamine, and stir until uniformly dispersed. Then, stir at 200 rpm at 20°C for 17 hours. After the reaction, place the reaction solution in a 3.5 kDa dialysis bag and dialyze against deionized water for 2 days to obtain a gallic acid-oxidized hyaluronic acid mixture.

[0059] Weigh 1 part by weight of a gallic acid-oxidized hyaluronic acid mixture and 2 parts by weight of a chitosan dispersion (chitosan and anhydrous ethanol are mixed in a weight ratio of 1:110 and placed in an ultrasonic disperser, and ultrasonically treated at a power of 400 W for 20 minutes to obtain a chitosan dispersion) and stir the mixture. Then, place the mixture in a 37°C water bath and let it stand until a glue is formed to complete the preparation of the bioadhesive.

[0060] Example 3:

[0061] A method for preparing an environmentally friendly and degradable bioadhesive comprises the following steps:

[0062] Weigh 1 part by weight of the preactivated gallic acid mixture obtained in Preparation Example 3, 7 parts by weight of the preactivated oxidized hyaluronic acid mixture obtained in Preparation Example 6, and 0.02 parts by weight of 1,6-hexanediamine, and stir until uniformly dispersed. Then, stir at 200 rpm at 25°C for 20 hours. After the reaction, place the reaction solution in a dialysis bag with a cutoff of 3.5 kDa and dialyze against deionized water for 2 days to obtain a gallic acid-oxidized hyaluronic acid mixture.

[0063] Weigh 1 part by weight of a gallic acid-oxidized hyaluronic acid mixture and 3 parts by weight of a chitosan dispersion (chitosan and anhydrous ethanol are mixed in a weight ratio of 1:120 and placed in an ultrasonic disperser, and ultrasonically treated at a power of 400 W for 20 minutes to obtain a chitosan dispersion) and stir the mixture. Then, place the mixture in a 37°C water bath and let it stand until a glue is formed to complete the preparation of the bioadhesive.

[0064] Comparative Example 1:

[0065] A method for preparing an environmentally friendly and degradable bioadhesive comprises the following steps:

[0066] Weigh 1 part by weight of the preactivated gallic acid mixture obtained in Preparation Example 3, 7 parts by weight of the preactivated oxidized hyaluronic acid mixture obtained in Preparation Example 7, and 0.02 parts by weight of 1,6-hexanediamine, and stir until uniformly dispersed. Then, stir at 200 rpm at 25°C for 20 hours. After the reaction, place the reaction solution in a 3.5 kDa dialysis bag and dialyze against deionized water for 2 days to obtain a gallic acid-oxidized hyaluronic acid mixture.

[0067] Weigh 1 part by weight of a gallic acid-oxidized hyaluronic acid mixture and 3 parts by weight of a chitosan dispersion (chitosan and anhydrous ethanol are mixed in a weight ratio of 1:120 and placed in an ultrasonic disperser, and ultrasonically treated at a power of 400 W for 20 minutes to obtain a chitosan dispersion) and stir the mixture. Then, place the mixture in a 37°C water bath and let it stand until a glue is formed to complete the preparation of the bioadhesive.

[0068] Comparative Example 2:

[0069] A method for preparing an environmentally friendly and degradable bioadhesive comprises the following steps:

[0070] Weigh 1 part by weight of the preactivated gallic acid mixture obtained in Preparation Example 3, 7 parts by weight of the preactivated oxidized hyaluronic acid mixture obtained in Preparation Example 6, and 0.02 parts by weight of ethylenediamine, and stir until uniformly dispersed. Stir the mixture at 200 rpm at 25°C for 20 hours. After the reaction, place the reaction mixture in a 3.5 kDa dialysis bag and dialyze against deionized water for 2 days to obtain a gallic acid-oxidized hyaluronic acid mixture.

[0071] Weigh 1 part by weight of a gallic acid-oxidized hyaluronic acid mixture and 3 parts by weight of a chitosan dispersion (chitosan and anhydrous ethanol are mixed in a weight ratio of 1:120 and placed in an ultrasonic disperser, and ultrasonically treated at a power of 400 W for 20 minutes to obtain a chitosan dispersion) and stir the mixture. Then, place the mixture in a 37°C water bath and let it stand until a glue is formed to complete the preparation of the bioadhesive.

[0072] Comparative Example 3:

[0073] A method for preparing an environmentally friendly and degradable bioadhesive comprises the following steps:

[0074] Weigh 1 part by weight of the preactivated gallic acid mixture obtained in Preparation Example 3, 7 parts by weight of the preactivated oxidized hyaluronic acid mixture obtained in Preparation Example 6, and 0.02 parts by weight of 1,8-octanediamine, and stir until uniformly dispersed. Then, stir at 200 rpm at 25°C for 20 hours. After the reaction, place the reaction solution in a 3.5 kDa dialysis bag and dialyze against deionized water for 2 days to obtain a gallic acid-oxidized hyaluronic acid mixture.

[0075] Weigh 1 part by weight of a gallic acid-oxidized hyaluronic acid mixture and 3 parts by weight of a chitosan dispersion (chitosan and anhydrous ethanol are mixed in a weight ratio of 1:120 and placed in an ultrasonic disperser, and ultrasonically treated at a power of 400 W for 20 minutes to obtain a chitosan dispersion) and stir the mixture. Then, place the mixture in a 37°C water bath and let it stand until a glue is formed to complete the preparation of the bioadhesive.

[0076] Comparative Example 4:

[0077] A method for preparing an environmentally friendly and degradable bioadhesive comprises the following steps:

[0078] Weigh 1 part by weight of the preactivated gallic acid mixture obtained in Preparation Example 3, 7 parts by weight of the preactivated oxidized hyaluronic acid mixture obtained in Preparation Example 6, and 0.02 parts by weight of 1,8-octanediamine, and stir until uniformly dispersed. Then, stir at 200 rpm at 25°C for 20 hours. After the reaction, place the reaction solution in a 3.5 kDa dialysis bag and dialyze against deionized water for 2 days to obtain a gallic acid-oxidized hyaluronic acid mixture.

[0079] Weigh 1 part by weight of a gallic acid-oxidized hyaluronic acid mixture, 3 parts by weight of a sodium alginate dispersion (sodium alginate and anhydrous ethanol are mixed in a weight ratio of 1:120 and placed in an ultrasonic disperser, and ultrasonically treated at a power of 400 W for 20 minutes to obtain a sodium alginate dispersion) and 0.01 part by weight of a calcium chloride solution (the mass concentration of the calcium chloride solution is 20%), mix and stir, then place in a 37°C water bath and let stand until a glue is formed to complete the preparation of the bioadhesive.

[0080] Comparative Example 5:

[0081] A method for preparing an environmentally friendly and degradable bioadhesive comprises the following steps:

[0082] Weigh 1 part by weight of the preactivated gallic acid mixture obtained in Preparation Example 3, 7 parts by weight of the preactivated oxidized hyaluronic acid mixture obtained in Preparation Example 6, and 0.02 parts by weight of 1,8-octanediamine, and stir until uniformly dispersed. Then, stir at 200 rpm at 25°C for 20 hours. After the reaction, place the reaction solution in a 3.5 kDa dialysis bag and dialyze against deionized water for 2 days to obtain a gallic acid-oxidized hyaluronic acid mixture.

[0083] Weigh 1 part by weight of a gallic acid-oxidized hyaluronic acid mixture and 3 parts by weight of a carboxymethyl chitosan dispersion (carboxymethyl chitosan and anhydrous ethanol are mixed in a weight ratio of 1:120 and placed in an ultrasonic disperser, and ultrasonically treated at a power of 400 W for 20 minutes to obtain a carboxymethyl chitosan dispersion), mix and stir, then place in a 37°C water bath and let stand until a glue is formed to complete the preparation of the bioadhesive.

[0084] (1) Adhesive strength test of bioadhesive:

[0085] Fresh pigskin was cut into 5 cm long and 2 cm wide strips after the fat layer was removed, leaving the dermis. The bioadhesives prepared in Examples 1-3 and Comparative Examples 1-5 were then applied to the pigskin surface. The strips were then pressed against another piece of pigskin at a pressure of 8 kPa for 30 seconds to achieve complete adhesion. The adhesive strength was then tested using a universal testing machine at a tensile speed of 10 mm / min at a temperature of 25°C ± 2°C. The structures are shown in Table 1 below.

[0086] Table 1 Adhesion strength performance

[0087]

[0088]

[0089] (2) Degradation test:

[0090] The bioadhesives prepared in Examples 1-3 and Comparative Examples 1-5 were sealed and cured in a 37°C constant temperature incubator for 6 hours. They were then removed and immersed in 10 mL of PBS buffer (pH 7.4) and incubated at 37°C for another 6 days. The presence of cured bioadhesive in the buffer was observed. The results are shown in Table 2 below.

[0091] Table 2 Degradation behavior statistics

[0092]

[0093]

[0094] (3) Antibacterial test:

[0095] The bioadhesive prepared in Examples 1 to 3 and Comparative Examples 1 to 5 was applied to the surface of beef extract peptone agar culture medium. After solidification, the bacterial solution with a concentration of 1×10 8 The Staphylococcus aureus liquid was evenly smeared on the surface of the beef extract peptone agar medium solidified with a biological adhesive, and then inverted and cultured in a constant temperature incubator at 37°C for 24 hours. The number of bacteria was then measured and the inhibition rate was calculated (the beef extract peptone agar medium without adding biological adhesive was used as the blank group. After the blank group was cultured for 24 hours, it was placed under ultraviolet light for 12 hours for sterilization). The results are shown in Table 3 below.

[0096] Table 3 Antibacterial properties

[0097] Sources Antibacterial rate (%) Example 1 53.8 Example 2 55.4 Example 3 56.3 Comparative Example 1 55.7 Comparative Example 2 55.4 Comparative Example 3 56.1 Comparative Example 4 20.5 Comparative Example 5 55.1 Blank group 65.3

[0098] (4) Air permeability test:

[0099] According to ASTM D 737, the air permeability of the bioadhesives prepared in Examples 1 to 3 and Comparative Examples 1 to 5 was tested using a fully automatic air permeability meter with a test area of ​​20 cm 2 , the test pressure is 100Pa, and the results are shown in Table 4 below.

[0100] Table 4 Air permeability

[0101] Sources Air permeability (mm / s) Example 1 3.1 Example 2 3.4 Example 3 3.5 Comparative Example 1 3.2 Comparative Example 2 1.8 Comparative Example 3 1.5 Comparative Example 4 3.3 Comparative Example 5 3.1 Blank group 3.2

[0102] The following conclusions can be drawn from Tables 1 to 4 above:

[0103] (1) It can be seen from Examples 1 to 3 that the bioadhesive formed by the present invention by mixing gallic acid and oxidized hyaluronic acid with a diamine crosslinker to obtain a gallic acid-oxidized hyaluronic acid mixture, which is then mixed and cross-linked with an aminopolysaccharide dispersion, has good adhesive properties, antibacterial properties and breathability.

[0104] (2) Comparative Example 1 shows that the bioadhesive prepared by this system has poor adhesion performance. This may be because the oxidation intensity of hyaluronic acid in this system is too high, and the hyaluronic acid vicinal dihydroxyl group breaks to produce more aldehyde functional groups. The aldehyde groups on the prepared oxidized hyaluronic acid consume more amino groups on the chitosan structure, which makes the oxidative polymerization cross-linking between the phenolic hydroxyl groups on gallic acid and the amino groups on chitosan poor, thus resulting in poor adhesion performance of the bioadhesive finally prepared.

[0105] (3) Comparative Example 2 shows that the bioadhesive prepared by this system has poor air permeability. This may be because the carbon chain of ethylenediamine is relatively short, which has a poor effect on improving the flexibility of the molecular chain in the bioadhesive. The degree of cross-linking under the conditions of this system may be high, which results in fewer pores in the cross-linked bioadhesive, affecting the air permeability.

[0106] (4) Comparative Example 3 shows that the bioadhesive prepared by this system has poor air permeability and poor adhesion. This may be because the carbon chain of 1,8-octanediamine is too long in this system. When the carbon chain is too long, the movement of the molecular chain segments may be restricted, resulting in decreased air permeability. At the same time, an excessively long carbon chain may also lead to an increase in rigidity, which in turn affects its adhesion performance.

[0107] (5) Comparative Example 4 shows that the bioadhesive prepared by this system has poor antibacterial properties. This may be because in this system, although sodium alginate can be cross-linked with the gallic acid-oxidized hyaluronic acid mixture by hydrogen bonding and calcium ion chelation, sodium alginate does not have antibacterial properties, which has poor ability to weaken bacterial infection during wound recovery.

[0108] (6) Comparative Example 5 shows that the bioadhesive prepared by this system has poor adhesion performance. This may be because although carboxymethyl chitosan has the same amino functional group as chitosan, carboxymethyl chitosan is a carboxymethylated derivative of chitosan, and a carboxymethyl group is introduced into its structure. On the one hand, this group may replace part of the amino structure in chitosan, resulting in a decrease in the amino content. On the other hand, it may produce a steric effect in the spatial structure, resulting in poor cross-linking with the aldehyde group on gallic acid-oxidized hyaluronic acid in the amount used in this system, and poor adhesion performance.

[0109] The embodiments described above provide a detailed description of the technical solutions and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the present invention. Various changes and modifications may be made to the present invention without departing from the spirit and scope of the present invention, and such changes and modifications fall within the scope of the present invention as claimed.

Claims

1. A method for preparing an environmentally friendly and degradable bioadhesive, characterized in that: The preparation method comprises the following steps: The preactivated gallic acid mixture, the preactivated oxidized hyaluronic acid mixture, and the diamine cross-linking agent are reacted at 20° C. to 25° C. for 15 to 20 hours, and then dialyzed to obtain a gallic acid-oxidized hyaluronic acid mixture; The gallic acid-oxidized hyaluronic acid mixed solution and the aminopolysaccharide dispersion solution are mixed, stirred, and allowed to stand to obtain the bioadhesive; The preparation method of the pre-activated oxidized hyaluronic acid mixed solution comprises the following steps: Hyaluronic acid, deionized water, and sodium periodate are mixed and dispersed in a light-proof environment, and then reacted at 25°C to 30°C for 10 hours to 12 hours, followed by dialyzation and freezing to obtain oxidized hyaluronic acid. The oxidized hyaluronic acid, dimethyl sulfoxide, 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride and 1-hydroxybenzotriazole are mixed and dispersed and stirred at 10° C. to 15° C. for 15 min to 20 min to obtain the pre-activated oxidized hyaluronic acid mixed solution; The diamine crosslinking agent is 1,4-butanediamine or 1,6-hexanediamine; The aminopolysaccharide dispersion is prepared by mixing and dispersing chitosan and anhydrous ethanol in a weight ratio of 1:100-120.

2. The method for preparing an environmentally friendly and degradable bioadhesive according to claim 1, characterized in that: The preparation method of the pre-activated gallic acid mixed solution comprises the following steps: Gallic acid, dimethyl sulfoxide, 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride and 1-hydroxybenzotriazole are mixed and dispersed, and stirred at 10° C. to 15° C. for activation for 15 min to 20 min to obtain the pre-activated gallic acid mixture.

3. The method for preparing an environmentally friendly and degradable bioadhesive according to claim 2, characterized in that: The weight ratio of gallic acid: dimethyl sulfoxide: 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride: 1-hydroxybenzotriazole is 1:200-300: 1-1.5: 1-1.

5.

4. The method for preparing an environmentally friendly and degradable bioadhesive according to claim 1, characterized in that: The weight ratio of the hyaluronic acid: deionized water: sodium periodate is 1:100-150:0.5-1.

5. The method for preparing an environmentally friendly and degradable bioadhesive according to claim 1, characterized in that: The weight ratio of the oxidized hyaluronic acid: dimethyl sulfoxide: 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride: 1-hydroxybenzotriazole is 1:150-200:1-1.5:1-1.

5.

6. The method for preparing an environmentally friendly and degradable bioadhesive according to claim 1, characterized in that: The weight ratio of the pre-activated gallic acid mixed solution: the pre-activated oxidized hyaluronic acid mixed solution: the diamine cross-linking agent is 1:5-7:0.01-0.

02.

7. The method for preparing an environmentally friendly and degradable bioadhesive according to claim 1, characterized in that: The weight ratio of the gallic acid-oxidized hyaluronic acid mixed solution to the aminopolysaccharide dispersion is 1:1-3.

8. A bioadhesive prepared by the method for preparing an environmentally friendly and degradable bioadhesive according to any one of claims 1 to 7.

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